While the party Out of Power tends to do better in the next midterm, it is by no means a sure thing, and Republicans have seemed to outperformed Democrats in this respect, probably in part because midterm turnout favors older and whiter which, well, you can finish this sentence.

Special elections and off year elections such as Virginia can give some indications about what to expect for turnout in the midterms. And I am finding those indications encouraging.